18 results on '"damp-heat"'
Search Results
2. Preparation and properties of AZO/Ag/AZO thin films on PMMA substrates
- Author
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XU Qingyuan, ZHANG Yunsheng, CHEN Chen, FENG Haibing, HUANG Peng, and ZU Chengkui
- Subjects
pmma substrate ,azo/ag/azo ,lamination ,damp-heat ,transparent heaters ,Motor vehicles. Aeronautics. Astronautics ,TL1-4050 - Abstract
AZO/Ag/AZO transparent conductive films were prepared on PMMA substrate by DC magnetron sputtering at low temperature (70 ℃). The effect of AZO sputtering power on the structure and properties of AZO/Ag/AZO thin films were investigated. In order to encapsulate AZO/Ag/AZO films, the films were laminated with another uncoated PMMA substrate and polyurethane film. Damp and heat resistance and heating performance of this laminated structure were discussed. The morphology and structure of the films were characterized by SEM, XRD and AFM. The results show that the sputtering power of AZO affects the surface energy of AZO layer and the crystallization of AZO/Ag/AZO films. The AZO/Ag/AZO films which prepared with AZO sputtering power of 100W and 150W exhibit the best performance with a low sheet resistance of 3.7 Ω/sq and a high transmittance of 86.1% at room temperature. The optical and electrical properties of PMMA laminated structure remain stable after 30 days of damp-heat experiment. The temperature-time curve during the heating process of the PMMA laminated structure at room temperature shows fast temperature response time and good temperature uniformity under 5 V DC voltage. The PMMA laminated structure exhibits saturation temperature stability in cold convection air (−10-−40 ℃).
- Published
- 2023
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- View/download PDF
3. 有机玻璃基底 AZO/Ag/AZO 复合薄膜 的制备与性能.
- Author
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徐清源, 张运生, 陈 琛, 冯海兵, 黄 鹏, and 祖成奎
- Subjects
SURFACE energy ,DC sputtering ,MAGNETRON sputtering ,COLD (Temperature) ,LOW temperatures ,EXCIMER lasers - Abstract
Copyright of Journal of Aeronautical Materials is the property of Editorial Board of Journal of Aeronautical Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
- Full Text
- View/download PDF
4. Damp‐heat induced degradation in photovoltaic modules manufactured with passivated emitter and rear contact solar cells.
- Author
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Kyranaki, Nikoleta, Smith, Alex, Yendall, Keith, Hutt, David A., Whalley, David C., Gottschalg, Ralph, and Betts, Thomas R.
- Subjects
SOLAR cells ,ETHYLENE-vinyl acetate ,SURFACE passivation ,POLYETHYLENE terephthalate ,ACETIC acid ,BUILDING-integrated photovoltaic systems - Abstract
Corrosion is one of the main PV module failure mechanisms, as it can cause severe electrical performance degradation in PV modules exposed to hot and humid environments. Moisture penetrating a photovoltaic (PV) module may react with the metallic components causing corrosion. In addition, acetic acid which is produced by hydrolysis of ethylene vinyl acetate (EVA), the most common encapsulant, may further degrade metallic components. Corrosion is one of the main PV module failure mechanisms, as it can cause severe electrical performance degradation in PV modules exposed to hot and humid environments. The specific chemical reactions involved in the corrosion mechanisms for the different components are well understood. However, which of these causes the most serious degradation in the field, and therefore, most severe power loss is unknown. Moreover, the severity of corrosion in the absence of acetic acid is not yet well researched. This work distinguished between the front and rear side corrosion mechanisms and identified the different electrical signatures observed due to them. The experiment included damp‐heat (DH) conditioning of single‐cell mini‐modules, containing passivated emitter and rear contact (PERC) solar cells, laminated with a polyethylene terephthalate (PET) based backsheet. Furthermore, half‐encapsulated PERC PV cells were tested, with either the front or the rear side exposed. Electrical and material characterisation were conducted for the investigation of the sample degradation, and the performance decrease, related to the degradation of the rear surface passivation, was examined. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
5. 从"浊邪害清"论"湿热致中".
- Author
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温雅, 许永楷, 孙美灵, 郭永胜, and 张思超
- Abstract
Because people nowadays are addicted to eating too much fat, sweet food with thick taste, the incidence of stroke with damp-heat pattern is constantly increasing ・ Through combing the theoretical connotation and origins of u turbidity, u clear orifice", and u turbid evil invading the clear orifice", this article clarifies that damp heat is an important cause that cannot be ignored in the occurrence and development of stroke・ The causes of dampinclude external contraction and internal injury・ Dampheat obstructs the qi movement in the middle jiao, and blocks clear orifice in the upper part of the body, leading to the symptoms of the head and face, and even inducing the occurrence of stroke. Ye Tianshi5 s theory of u turbid evil invading the clear orificecan be regarded as a general exposition of u damp-heat leading to stroke ", so the diagnosis, treatment and prevention of damp-heat pattern should be emphasized ・ Based on the hypothesis of u brain-intestine interlink age, the core organs affected for the disease of stroke with damp-heat pattern are the brain, spleen, stomach and intestine・ To prevent stroke due to damp - heat, the above ・HientiorLe(l organs should be addressed by clearing dampness and heat, unblocking the fu organs and clearing orifices・ The theory of u turbid evil invading the clear orificeand the above-mentioned therapeutic methods are all derived from the theory and treatment experience of febrile disease・ Besides, therapies such as "differentiating and dispelling pathogenic factors from the three jiao" and u nourishing yin and promoting generation of body fluids" are also used in the treatment of stroke・ Therefore, the theory and experience of febrile disease may provide new ideas and methods for the prevention and treatment of stroke・ [ABSTRACT FROM AUTHOR]
- Published
- 2021
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6. Therapeutic effectiveness of Lishi Oral Liquid combined with levocetirizine in treating atopic dermatitis: A randomized double-blind placebo-controlled clinical trial
- Author
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Jingxiu Chai, Jie Ren, Kexiang Yan, Feng Xu, Ying Ma, Xiaohua Zhu, Fang Yan, Yongsheng Yang, Chaoying Gu, Jinfeng Wu, and Jinhua Xu
- Subjects
atopic dermatitis ,chinese medicine ,damp-heat ,clinical trial ,Other systems of medicine ,RZ201-999 - Abstract
Objective: To observe the efficacy and safety of Lishi Oral Liquid (LOL), a Chinese herbs formula, combined with levocetirizine, an antihistamine drug, in patients with damp-heat atopic dermatitis (AD). Methods: A randomized double-blind placebo-controlled clinical trial was conducted. Ninety patients diagnosed with damp-heat atopic dermatitis were randomly assigned to Lishi Oral Liquid group and control group at the ratio of 1:1. Patients were given one Lishi Oral Liquid or placebo three times per day. Both groups were treated with allantoin and vitamin E cream by topical use and levocetirizine by oral administration. Patients were followed up at the second and fourth week. The primary outcome was the scoring of atopic dermatitis (SCORAD). The secondary outcomes were visual analogue scale (VAS) and dermatology life quality index (DLQI). Results: After two weeks of treatment, there were statistical differences in SCORAD between these two groups (P
- Published
- 2019
- Full Text
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7. Chronic Idiopathic Pruritus Using Traditional Chinese Dietary Considerations.
- Author
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Hartmann, Jennifer L.
- Subjects
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DIET in disease , *DIET therapy , *DIETARY supplements , *ITCHING , *CHINESE medicine , *TREATMENT effectiveness - Abstract
Chronic ideopathic pruritus is an itch originating from unknown sources that lasts greater than six weeks. A 30-year-old female reported a chief complaint of chronic idiopathic pruritus. From a traditional Chinese medicine perspective she displayed signs and symptoms consistent with Spleen qi deficiency with accumulation of Damp-Heat, Liver qi stagnation and Blood deficiency leading to deficient and stagnant Heat stirring Wind. She had been previously seen by an internist, four dermatologists, two neurologists, and an allergist at the Mayo Clinic, showing inconclusive results of all biomedical tests. While there were clear pathophysiological mechanisms within traditional Chinese medicine that affected this case, the patient was unusually slow to respond to treatment. Careful case management and the introduction of traditional Chinese dietary considerations ultimately proved to be an effective intervention for this patient. This case history shows the need for further research to determine efficacy and establish effective mechanisms of action for treatment of this condition. [ABSTRACT FROM AUTHOR]
- Published
- 2020
8. Experimental study of observed defects in mini-modules based on crystalline silicone solar cell under damp heat and thermal cycle testing.
- Author
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Faye, Issa, Ndiaye, Ababacar, Gecke, Rudolph, Blieske, Ulf, Kobor, Diouma, and Camara, Moussa
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THERMOCYCLING , *THERMODYNAMIC cycles , *SOLAR cells , *SILICON solar cells , *INSPECTION & review , *ELECTROLUMINESCENCE - Abstract
• Consumer type multicrystalline modules are investigated in two types of conditions: thermal cycle and damp heat testing. • Visual inspection, thermography, electroluminescence and IV-curve measurement help us for the investigation. • The results show that, corrosion, hot spot and delamination are the main degradation observed. In this study, consumer type multicrystalline modules are investigated. To assess the long-term reliability of photovoltaic (PV) multicrystalline modules, extended thermal cycling and damp heat testing were performed. This study focused on four multicrystalline modules. Two modules were subjected to 85 °C/85% damp heat testing at 1000 h and 1300 h, respectively. The other two modules were subjected to thermal cycle test of 55 cycles and 66 cycles, respectively. After testing, all 4 solar panels were investigated with the help of visual inspection, thermography, electroluminescence and IV-curve measurements. The main degradations observed were corrosion, hot spot and delamination. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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9. 中医辨体施护在高脂血症患者中的应用及研究进展.
- Author
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陈兰兰 and 王益平
- Abstract
Copyright of Nursing of Integrated Traditional Chinese & Western Medicine is the property of Journal of Clinical Nursing in Practice (Editorial Board, Shanghai Jiao Tong University Press) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2018
- Full Text
- View/download PDF
10. Damp-heat induced degradation in photovoltaic modules manufactured with passivated emitter and rear contact solar cells
- Author
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Kyranaki, N., Smith, A., Yendall, K., Hutt, D.A., Whalley, D.C., Gottschalg, Ralph, Betts, T.R., and Publica
- Subjects
corrosion ,damp-heat ,durability ,PERC ,PV modules - Abstract
Corrosion is one of the main PV module failure mechanisms, as it can cause severe electrical performance degradation in PV modules exposed to hot and humid environments. Moisture penetrating a photovoltaic (PV) module may react with the metallic components causing corrosion. In addition, acetic acid which is produced by hydrolysis of ethylene vinyl acetate (EVA), the most common encapsulant, may further degrade metallic components. Corrosion is one of the main PV module failure mechanisms, as it can cause severe electrical performance degradation in PV modules exposed to hot and humid environments. The specific chemical reactions involved in the corrosion mechanisms for the different components are well understood. However, which of these causes the most serious degradation in the field, and therefore, most severe power loss is unknown. Moreover, the severity of corrosion in the absence of acetic acid is not yet well researched. This work distinguished between the front and rear side corrosion mechanisms and identified the different electrical signatures observed due to them. The experiment included damp-heat (DH) conditioning of single-cell mini-modules, containing passivated emitter and rear contact (PERC) solar cells, laminated with a polyethylene terephthalate (PET) based backsheet. Furthermore, half-encapsulated PERC PV cells were tested, with either the front or the rear side exposed. Electrical and material characterisation were conducted for the investigation of the sample degradation, and the performance decrease, related to the degradation of the rear surface passivation, was examined.
- Published
- 2022
11. Changes of solar cell parameters during damp-heat exposure.
- Author
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Zhu, Jiang, Koehl, Michael, Hoffmann, Stephan, Berger, Karl Anton, Zamini, Shokufeh, Bennett, Ian, Gerritsen, Eric, Malbranche, Philippe, Pugliatti, Paola, Di Stefano, Agnese, Aleo, Francesco, Bertani, Dario, Paletta, Fabrizio, Roca, Francesco, Graditi, Giorgio, Pellegrino, Michele, Zubillaga, Oihana, Iranzo, F. J. Cano, Pozza, Alberto, and Sample, Tony
- Subjects
SOLAR cells ,SOLAR energy ,PHOTOVOLTAIC cells ,ENERGY conversion ,SILICON ,HEAT ,THERMOCHEMISTRY - Abstract
The electrical ageing of photovoltaic modules during extended damp-heat tests at different stress levels is investigated for three types of crystalline silicon photovoltaic modules with different backsheets, encapsulants and cell types. Deploying different stress levels allows determination of an equivalent stress dose function, which is a first step towards a lifetime prediction of devices. The derived humidity dose is used to characterise the degradation of power as well as that of the solar cell's equivalent circuit parameters calculated from measured current-voltage characteristics. An application of this to the samples demonstrates different modes in the degradation and thus enables better understanding of the module's underlying ageing mechanisms. The analysis of changes in the solar cell equivalent circuit parameters identified the primary contributors to the power degradation and distinguished the potential ageing mechanism for each types of module investigated in this paper. © 2016 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd. © 2016 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
12. Therapeutic effectiveness of Lishi Oral Liquid combined with levocetirizine in treating atopic dermatitis: A randomized double-blind placebo-controlled clinical trial
- Author
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Chaoying Gu, Jinhua Xu, Xiaohua Zhu, Yongsheng Yang, Jie Ren, Fang Yan, Feng Xu, Jingxiu Chai, Jinfeng Wu, Kexiang Yan, and Ying Ma
- Subjects
0301 basic medicine ,Drug ,medicine.medical_specialty ,damp-heat ,medicine.medical_treatment ,media_common.quotation_subject ,chinese medicine ,Traditional Chinese medicine ,Placebo ,Levocetirizine ,Double blind ,Other systems of medicine ,030207 dermatology & venereal diseases ,03 medical and health sciences ,0302 clinical medicine ,medicine ,media_common ,atopic dermatitis ,business.industry ,clinical trial ,Atopic dermatitis ,medicine.disease ,Dermatology ,Clinical trial ,030104 developmental biology ,Antihistamine ,business ,RZ201-999 ,medicine.drug - Abstract
Objective: To observe the efficacy and safety of Lishi Oral Liquid (LOL), a Chinese herbs formula, combined with levocetirizine, an antihistamine drug, in patients with damp-heat atopic dermatitis (AD). Methods: A randomized double-blind placebo-controlled clinical trial was conducted. Ninety patients diagnosed with damp-heat atopic dermatitis were randomly assigned to Lishi Oral Liquid group and control group at the ratio of 1:1. Patients were given one Lishi Oral Liquid or placebo three times per day. Both groups were treated with allantoin and vitamin E cream by topical use and levocetirizine by oral administration. Patients were followed up at the second and fourth week. The primary outcome was the scoring of atopic dermatitis (SCORAD). The secondary outcomes were visual analogue scale (VAS) and dermatology life quality index (DLQI). Results: After two weeks of treatment, there were statistical differences in SCORAD between these two groups ([Formula: see text]), whereas VAS and DLQI showed no statistical differences. There were significant differences in SCORAD and VAS between two groups at the end of four weeks of treatment ([Formula: see text]). However, no significant differences were observed in DLQI after four weeks of treatment. No serious adverse event was found during this clinical trial. Conclusion: LOL combined with levocetirizine is effective and safe for damp-heat AD treatment.
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- 2019
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13. Traditional Chinese Veterinary Medicine Diagnosis and Treatment of Acquired Infertility in Female Horses and Dogs.
- Author
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Xiuhui Zhong and Yantao Zhao
- Subjects
- *
CHINESE medicine , *VETERINARY medicine , *ANIMAL infertility , *ACUPUNCTURE , *CONGENITAL disorders , *VETERINARY therapeutics - Abstract
Acquired female infertility from a traditional Chinese veterinary medical (TCVM) perspective can be associated with Deficiency or Excess patterns. There are 6 patterns of acquired female infertility commonly diagnosed in TCVM practice. The 6 patterns are: 1) Kidney Qi and Blood Deficiency, 2) Kidney Yin Deficiency, 3) Kidney Yang Deficiency or Cold uterus, 4) Excess Phlegm and Damp, 5) Liver Qi and Blood Stagnation and 6) Damp-Heat. Malnutrition or over-working can result in infertility from Kidney Qi and Blood Deficiency or Kidney Yin Deficiency. Obesity will cause Stagnation in the uterus with an Excess of Phlegm and Damp, making it impossible for oocytes to be released or connect with sperm. Cold Deficiency of the uterus or Kidney Yang Deficiency will damage the Chong Channel and the Conception Vessel (Ren Channel) and lead to infertility. Stagnant Qi and Blood in the Liver can impair uterine reproductive function and lead to infertility. Damp-Heat flows downward to the uterus and infertility results. Each pattern has characteristic findings on the TCVM examination, may require treatment of different acupoints and most importantly require different Chinese herbal medicines. Administering the incorrect Chinese herbal medicine could worsen the problems and harm the animal. Thus, when diagnosing infertility, one should attempt to identify the correct pattern, so that proper treatment can be administered. The pathogenesis, clinical signs, treatment principles, acupuncture points and Chinese herbal medicines are described for each pattern. Infertility due to congenital defects and aging are not discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
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14. Effect of Backsheet Properties on PV Encapsulant Degradation during Combined Accelerated Aging Tests
- Author
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Mansour, Barretta, Bauermann, Pitta, Oreski, Schueler, Philipp, and Gebhardt
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backsheet ,damp-heat ,material combination ,photovoltaic (PV) module ,accelerated aging ,ultraviolet (UV), UV-DH combined ,encapsulant ,degradation - Abstract
Long-term photovoltaic (PV) module reliability is highly determined by the durability of the polymeric components (backsheet and encapsulation materials). This paper presents the result of experiments on encapsulant degradation influenced by the backsheet permeation properties. Towards this goal, one type of ethylene/vinyl acetate copolymer (EVA) was aged in glass/EVA/backsheet laminates in accelerated aging tests (up to 4000 h for Damp-Heat (DH) and up to 480 kWh/m2 for UV and UV-DH combined). The samples contained three backsheets with different permeation properties to examine their impact on EVA degradation. Thermal and chemical characterization shows that the EVA degradation is stronger with the glass&ndash, EVA&ndash, polyamide (PA)-based backsheet than with the polyethylene terephthalate (PET)-based backsheets. The higher oxygen transmission rate (OTR) of the PA-based backsheet may increase photo-oxidation and aggravating the degradation of EVA in the laminates. Furthermore, FTIR results were used to demonstrate the effect of damp heat exposure on the EVA interfaces, showing an accelerated degradation at the glass&ndash, EVA interface. The comparison of accelerated aging stress factors reveals that EVA suffers the strongest chemical and optical degradation when high UV, high temperature and high relative humidity are combined simultaneously.
- Published
- 2020
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15. The Influence of Laminate Design on Cell Degradation.
- Author
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Peike, Cornelia, Hoffmann, Stephan, Dürr, Ines, Weiß, Karl-Anders, and Koehl, Michael
- Abstract
Abstract: In this study, the influence of the PV laminate design on the silicon cell degradation was investigated. Laminates consisting of two different kinds of encapsulation (EVA and PVB) and three different back-sheet materials (TAPT, PA and a TPT foils) were manufactured. Standard cells with a two and three bus bar design were used as well as MWT cells. The laminates were subjected to a UV, heat and damp-heat aging tests. The degradation of the cell metallization was investigated by means of electroluminescence imaging, the degree of polymeric aging was determined by Raman spectroscopy. Special attention was paid to the spatial distribution of corrosion effects on the cell. A severe influence of the solar cell type, i.e. the metallization paste, could be shown. Furthermore, a strong dependence of the degree of metallization degradation on the type of back-sheet material was found. An extensive UV aging for up to 180 kWh appeared to have no influence on the metallization corrosion. [Copyright &y& Elsevier]
- Published
- 2013
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16. Investigation on the function tropism of Tiaoqin and Kuqin (different specification of Scutellaria baicalensis) by comparing their curative effect on different febrile disease model.
- Author
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Ren, Yongshen, Liang, Shuai, Zheng, Yao, Deng, Xin, Lei, Lei, Ai, Jiao, Li, Yanqiu, Zhang, Tianpei, Chen, Linlin, Mei, Zhinan, Cheng, Yung-Chi, and He, Caijing
- Subjects
- *
ANIMAL experimentation , *BIOLOGICAL models , *BODY temperature , *COMPARATIVE studies , *FEVER , *HERBAL medicine , *CHINESE medicine , *RATS , *PLANT roots , *WATER , *PHENOMENOLOGICAL biology , *TREATMENT effectiveness , *IN vivo studies - Abstract
Scutellaria baicalensis (S. baicalensis) is the root of S. baicalensis Georgi. In traditional Chinese medicine it is divided into Tiaoqin (TQ, 1–3 years old) and Kuqin (KQ, more than 3 years old). However, the differences in TQ and KQ efficacy and their exact mechanisms are still unclear. This study aimed to clarify the difference in the efficacy of TQ and KQ in relation to different fever types (damp heat and hyperpyrexia) by using rat models, as well as to determine the primary molecular mechanism. This study compared the compositional content of TQ and KQ by UPLC-MS/MS. Then, rat models of hyperpyrexia (HP, LPS) and damp heat (DH, high-fat and high-sugar diet feeding + fumigation in artificial climate chamber + E. coli injection) were established and their clinical symptoms, blood biochemistry, histopathological sections, cell cytokines and protein expression were compared following treatment with TQ or KQ. Finally, the mechanisms underpinning the differences observed for TQ and KQ were determined by measuring the components of these treatments in different target organs. This study identified 31 compounds in the water extracts of both TQ and KQ, which differed significantly in their relative content. TQ and KQ showed different functional tropism in HP and DH model rats. Baicalin, wogonoside, oroxin A, baicalein, wogonin and oroxylin A appeared to be the basic functional components responsible for the functional tropism hypothesis, while the remaining compounds appeared to be the efficacy-oriented components. In addition, the difference in pharmacodynamics between TQ and KQ may be related to their absorption in vivo , which was consistent with the hypothesis of functional tropism proposed in this work. In this study we adopted TQ and KQ―different specifications of Scutellaria baicalensis with similar chemical components―as a case study to systematically reveal the functional tropism of Chinese herbal medicine (CHM). The results showed that TQ and KQ contain the basic functional components to enable the basic function of 'clearing heat', while the variation in compositional content may result in their different therapeutic effects. A greater understanding and utilisation of the functional tropism of CHM would enormously improve the accuracy and scientific basis for the application of CHM medication, as well as in promoting the multi-function mechanism of CHM and guiding new drug development of CHM. This work is based on the difference between TQ and KQ in efficacy and clinical usage in traditional Chinese medicine. Current research of this work provides new ideas for the development of TQ and KQ. Image 1 [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
17. The Influence of Laminate Design on Cell Degradation
- Author
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Ines Dürr, S. Hoffmann, Cornelia Peike, Karl-Anders Weiß, Michael Koehl, and Publica
- Subjects
Silicon cell ,Materials science ,damp-heat ,Cell degradation ,Damp heat ,Electroluminescence ,metallization ,Corrosion ,law.invention ,electroluminescence ,symbols.namesake ,Energy(all) ,law ,Solar cell ,symbols ,Forensic engineering ,Composite material ,Raman spectroscopy ,degradatiopn - Abstract
In this study, the influence of the PV laminate design on the silicon cell degradation was investigated. Laminates consisting of two different kinds of encapsulation (EVA and PVB) and three different back-sheet materials (TAPT, PA and a TPT foils) were manufactured. Standard cells with a two and three bus bar design were used as well as MWT cells. The laminates were subjected to a UV, heat and damp-heat aging tests. The degradation of the cell metallization was investigated by means of electroluminescence imaging, the degree of polymeric aging was determined by Raman spectroscopy. Special attention was paid to the spatial distribution of corrosion effects on the cell. A severe influence of the solar cell type, i.e. the metallization paste, could be shown. Furthermore, a strong dependence of the degree of metallization degradation on the type of back-sheet material was found. An extensive UV aging for up to 180 kWh appeared to have no influence on the metallization corrosion.
- Full Text
- View/download PDF
18. High-Quality Microcrystalline Silicon for Efficient Thin-Film Solar Cells Insights into Plasma and Material Properties
- Author
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Bugnon, Grégory, Ballif, Christophe, and Sculati-Meillaud, Fanny
- Subjects
p-i interface ,shunt quenching ,multi-junction ,microcrystalline silicon ,nanostructure ,mixed-phase material ,nucleation ,damp-heat ,micromorph ,PECVD ,doping ,amorphous silicon ,deposition ,VHF ,transverse conductivity ,compensation ,contamination ,anti-reflection ,nanoporous regions ,intrinsic stress ,surface morphology ,triple-junction ,plasma ,single-junction ,roughness ,optical layers ,electrical stability ,compressive stress ,boron cross-contamination ,high-efficiency ,silicon ,zinc oxide ,silicon oxide ,Photovoltaics ,excitation frequency ,thin films ,solar cells ,RF ,light trapping ,cracks - Abstract
This thesis investigates the link between the plasma deposition conditions and microcrystalline silicon (μc-Si:H) material quality for thin-film silicon photovoltaic applications. The role of interfaces and the μc-Si:H material quality on the device performance are analyzed in detail. The low absorption of μc-Si:H at long wavelengths requires the deposition of absorber layers with thicknesses of typically a few micrometers for use in multi-junction TF Si solar cells. The growth typically takes place on highly textured surfaces, which provide increased light absorption—often called light trapping—but which potentially induce structural defects in the film during its growth. Therefore, to further improve the TF Si technology, one of the main challenges is the identification of the determinant plasma deposition parameters that result in the growth of very high-quality μc-Si:H at an increased deposition rate on textured substrates that guarantee efficient light trapping. As a first approach to better understand the plasma conditions necessary for the growth of high-quality μc-Si:H, the roles of both the silane depletion fraction and the deposition pressure are studied in an industrial-type large-area KAI reactor. With increasing pressure and silane depletion, the μc-Si:H defect density is significantly lowered leading to improved solar cell performance. An estimation of the average energy with which ions impinge on the substrate supports the hypothesis that ion bombardment is mainly responsible for the observed differences. Then, a fundamental aspect of μc-Si:H deposition on highly textured substrates is highlighted: two different phases of μc-Si:H material contribute to the overall solar cell efficiency, both of which can drive cell performance. The first phase relates to the bulk material and dominates the performance of cells on flat substrates. However, on rough morphologies, substrate-induced defective localized nanoporous regions—the second phase—develop and are found to be significantly more sensitive to the plasma process conditions and substrate morphology than the bulk phase. The relative importance of this secondary defective phase is shown through the use of new damp-heat experiments. Silicon oxide doped layers are demonstrated to mitigate the influence of these nanoporous regions on the solar cell performance. Next, a comparative study of the plasma excitation frequencies of 13.56 MHz (RF) and 40.68 MHz (VHF) shows that, while both allow for the growth of very good-quality bulk material, the efficiency of VHF-prepared cells is always poorer compared to that of RF-prepared cells within the range of our study for growth rates below 5 Å s−1. This decrease in solar cell performance is related to a higher density of nanoporous regions in the VHF-prepared cells as evidenced by damp-heat experiments, leading to strong open-circuit voltage instabilities. Still, the use of VHF is shown to be beneficial at increased deposition rates, thanks to reduced ion bombardment and improved bulk material quality. The crucial interplay between μc-Si:H growth rate and substrate morphology with regard to the formation of nanoporous regions is further discussed for regimes with high deposition rates of around 10 Ås−1. It is shown that high-silane-depletion regimes with significantly reduced H2 flow rate or increased pressure lead to a denser μc-Si:H material but are associated with increased secondary gas-phase reactions and powder formation. The use of a reduced interelectrode distance is demonstrated to allow for the growth of μc-Si:H with significantly improved bulk material quality at higher growth rates. Plasma simulations performed in collaboration with the University of Patras are presented and suggest that improvements observed in the μc-Si:H material quality are related mainly to an increased contribution of less reactive silane monoradicals, such as SiH3 and Si2H5, to the growing film, as compared to highly reactive ones such as SiH2 and SiH. Then, in an effort to better understand the formation of these two distinct μc-Si:H phases, the intrinsic stress within μc-Si:H i-layers is studied and correlated with the bulk defect density. Further improvements to both μc-Si:H and a-Si:H solar cells are obtained by introducing a novel intrinsic silicon oxide buffer layer at the p -i interface. For μc -Si:H solar cells, all electrical parameters are improved unless the i -layer is significantly more amorphous-rich and high quality, in which case an improvement only in carrier collection in the blue region is observed. In a-Si:H solar cells the silicon oxide buffer is shown to lower light-induced degradation, which is one of the weak points of TF Si technology. Furthermore, for both a-Si:H and μc-Si:H solar cells, the buffer can also act as an efficient barrier to boron cross-contamination, eliminating the need for additional time-consuming processing steps such as a water flush for single-chamber processes. Overall, this work contributes to a better understanding of the μc-Si:H material requirements for PV applications and how they relate to the plasma deposition conditions. Based on all the aforementioned developments, significant progress has been made in the understanding and the fabrication of thin-film silicon solar cells based on μc-Si:H. An outstanding single-junction μc-Si:H solar cell of 10.9% was attained; to our knowledge this is the highest reported in the literature. This work also contributed to the development of very high-efficiency tandem and triple-junction thin-film silicon solar cells at PV-Lab.
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